Lieberman et al., U.S. Pat. No. 4,985,959 discloses, in FIGS. 1 and 3 though 5, end supports for a paint-applying cover sleeve of a paint roller assembly, each support containing a split tube bushing adapted to receive the metal axle of a paint roller handle (or “frame”). The bushing is frictionally retained on the axle and rotates within a cylindrical chamber defined in the end support.
Isaac U.S. Pat. No. 5,269,039, in FIGS. 2 through 5, discloses a sectional paint roller cover bearing assembly (or “cage”) having an end piece that surrounds a split sleeve which acts as a bushing. However, the bushing of Isaac is only retained by the end piece after either an extension or an end cap is inserted into the end piece. Several extensions may be used to form a longer roller assembly for supporting a longer cover, and a second bushing may be disposed in one of the extensions; however the only bearing surfaces for facilitating rotation of the roller on the axle of the roller frame are at the two ends, in the end piece and in the end cap.
Goldstein U.S. Pat. No. 5,210,899 discloses a paint roller cage, seen in FIGS. 1, 5, 7, and 9, having a series of offset or staggered outer semi-cylindrical surfaces that frictionally engage the interior of a small diameter paint roller cover sleeve. At least one bushing loosely fits within the confines of one of the semi-cylindrical chambers of the bearing and clamps around the metal axle of the paint roller handle. Except for an end cap at one end, each bearing surface is not cylindrical, but is defined by a pair of adjacent reduced diameter semi-cylindrical surfaces at each end of each semi cylindrical chamber. Goldstein makes no special provision for accurate rotation and lateral positioning of the bearing assembly about the axle, and it would appear from FIG. 10, that when the removable cover is not secured to the bearing assembly, Goldstein's bushings can easily fall out of the cylindrical chambers.
In Song Kim U.S. Pat. No. 7,120,963 there is disclosed a paint roller cage in the form of a cylindrical sleeve having a diameter of about 0.25″ to 1.0″, upon which the paint receiving cover material may be mounted, and into one end of which a single molded support bearing is inserted, the single support bearing having a first cylindrical chamber adapted for supporting the axle portion of the paint roller handle, typically a metal rod, and a second chamber coaxial with the first for receiving a single split bushing having an nominal internal diameter less than the diameter of the metal rod of the paint roller handle, with the dimensions of the second chamber being such that the bushing may rotate freely inside the second chamber, but is somewhat constrained longitudinally. The second chamber has a large lateral opening through which the split bushing may be inserted into the second chamber prior to insertion of the support into the sleeve. The inner surface of the sleeve functions as a cover for the lateral opening after the support and bushing have been inserted.
A traditional paint roller cover with a 0.5″ nap has a diameter of 1.5″ and a length of 9″, and with a conventional cage and frame weighs about 0.85 lbs, or fully loaded with paint weighs about 1.8 lbs. Moreover, traditional roller covers have lateral movement along the axle on average of 0.25″ resulting in walk off from the frame.
Simply reducing the length of a standard roller to reduce its weight results in a loss of efficiency in that more strokes are needed with shorter rollers to paint a given surface. Similarly, use of a standard length cover on a shorter frame results in asymmetric forces being applied to the cover and exacerbates the tendency of the rotating cover to deviate from the proper alignment with the frame. Therefore there is a need for a lightweight paint roller of standard length that can be used with a shorter and smaller frame but that nevertheless still maintains a proper alignment between the cover and the frame, thus facilitating precise and even coverage of the surface to be painted.